Sometimes you need to read a record, and hold that record
in the input buffer while you test for a specified condition before
a decision can be made about further processing. For example, the
ability to hold a record so that you can read from it again, if necessary,
is useful when you need to test for a condition before SAS creates
an observation from a data record. To do this, you can use the trailing
For example, to create a SAS data set that is a subset of a larger group of records, you might need to test for a condition to decide whether a particular record will be used to create an observation. The trailing at-sign placed before the semicolon at the end of an INPUT statement ...